1. Lab 9
Intro to Robots

2. Exercise 1:
Write the program described in class that makes a red line scan across a photo.
Program design:
picture = loadPicture(“mypicture.jpg”) copyPic = copyPicture(picture)
for each xCoordinate of copyPic:
draw a vertical red line
show(copyPic)
wait(0.2)
reconstruct the original pixels in copyPic from picture
copy vertical line in original picture to copy
def reconstructVerticalLine(pic1,pic2,x):
for each yCoordinate of pic2:
get pixel (pix1) from pic1 pixel (x,y)
get pixel (pix2) from pic2 pixel (x,y)
get three colors from pix1
assign three colors to pix2
Intro to Robots

3. I don’t like the name, call your new function filterRedAreas().
Exercise 2:
Rewrite findRedAreas() in the class notes to convert all really red areas to totally red (255,0,0) and the rest to black (0,0,0).
As a measure of “really red”, let’s say that pixels in the range (>200, <175, <175) are “really red”.
I don’t like the name, call your new function filterRedAreas().
Intro to Robots

4. Exercise 3:
Modify the program studied in class that finds the red center of a photograph to put a cross-hairs in the same picture.
Intro to Robots

5. Write a program that rotates a picture 90°.
Exercise 4:
Write a program that rotates a picture 90°.
Intro to Robots

6. Modify that program to put a cross-hairs at the center of the blob.
Exercise 5:
The second program we studied in class puts a vertical line through the center of the largest red blob in a picture.
Modify that program to put a cross-hairs at the center of the blob.
Idea for how to do this: Make a copy of the picture by rotating it 90 degrees. In the rotated picture find the x-coordinate of the vertical line through the largest red blob. Use this as the y-coordinate of a horizontal line in the original picture.
Intro to Robots